Operating mechanism for needle threading devices



H. ZINK ET AL March 27, 1956 OPERATING MECHANISM FOR NEEDLE THREADING DEVICES Filed March 31, 1954 ite OPERATING MECHANISM FOR NEEDLE THREADIN G DEVICES Hermann Zink and Herbert Wenz, Kaiserslautern, Germany, assignors to G. M. Pfafr A.-G., Kaiserslantern, Germany Application March 31, 1954, Serial No. 420,169 Claims priority, application Germany April 9, 1953 4 Claims. (Cl. 112-225) with the present invention are especially adapted for threading devices for machines including a needle bar oscillator operatively cooperating with the needle bar to cause movement of the needle bar.

In devices of this type for example as shown in U. S. application No. 335,723 of February 9, 1953, Patent No. 2,727,479 dated December 20, 1955, a bar carrying the threading hook is mounted on the machine arm or in the needle bar oscillator in bearings arranged parallel to the needle bar. Cooperating with a sliding member having a curved track and a spring arrangement, an operative relationship is automatically established between the guide bar for the threading device and the needle bar for alignment of the threading device with the eye of the needle. Furthermore, axial movement and rotation of the guide bar is effected. The sliding member is provided for operation with an operating lever downward movement of which causes the threading device to swing into the eye of the needle. The sliding member can be guided by means of a lug or the like in a plate on the head of the machine. In one arrangement the operating lever which is formed as a unitary structure with the sliding member extends forward through a slot out of the housing if the guide bar is arranged at the head of the machine, while it extends through a corresponding opening at the lower part of the head, if the guide bar is mounted on the needle bar oscillator and it is provided on an axial extension of the sliding member. In that case the handle is horizontally disposed. One part of the spring arrangement which cannot be accommodated in the housing thus remains exposed and visible '2 exactly in the line of vision of the operator upon the sewing area.

i In connection with this latter arrangement it has proven to be advantageous to have a member constitute the manipulating lever which is not a downwardly extending part of the slide as is the lever 20 in the arrangement illustrated in said application No. 335,723. The manipulating lever which projects from the lower end of the head on the one hand necessitates prolongation of the hook carrier, while on the other hand it moves back and forth with the needle bar during zig-zag stitching operations, a matter which is found to be annoying to the operator in the observation of the stitches. In the aforementioned arrangement a long slot in the head of the machines does not only adversely affect the appearance of the closed head conformation which is a desideratum, but it offers an entrance possibility for dust. Moreover, it is more advantageous to locate the manipulating lever for gripping to the rear of the machine head. Finally, a manipulating lever which is not rigidly connected with the threading means can be arranged in such a manner that owing to a gearing relationship the slot through which it extends from the housing can be much smaller than is the case tes atent stud 5 while the other end of the where direct operation is provided, i. e. where the manipulating lever is formed as a unitary structure with the sliding member.

The present invention solves the aforementioned problem with an operating arrangement where essentially the manipulating lever is a two armed lever which is separated from the sliding member, the pivot bolt of which lever is mounted on the head plate of the machine which covers the front opening. The possibility of separating the threading device from the manipulating or operating device which is thus afforded and the accurately guided interengagement of both during the mounting of the head plate is insured by a long slot provided in the end of the operating lever which is disposed opposite from the gripping handle. As to the threading device proper, a stud is provided on its sliding member which extends into the slot on the manipulating lever when the head plate is in place. Furthermore, there is located on the sliding member, parallel to the stud, a lug or the like which is guided in a vertical conformation on the head plate and prevents lateral turning of the threading device which would otherwise be possible with the new and nonrigid coupling between the manipulating lever and the sliding member defined by the engagement of the stud with the slot.

In accordance with the invention the operating lever is biased in non-operative direction by a spring which is supported on the head plate and which takes over a part of the functions which in older devices, such as referred to above are performed by the special spring system for the threading device, such as, for example, a spring disposed around the vertical bar which supports the threading hook.

The arrangement of the manipulating lever in accordance with the invention is possible in connection with both, threading hook guiding bars mounted in the head and also with such bars supported in the oscillator bar such as shown in said application Ser. No. 335,723.

An embodiment in accordance with the present invention is illustrated in the drawing in connection with a guiding bar arrangement in the oscillator bar.

Fig. l is a perspective illustration of the threading device disposed in the machine head and of the components of the manipulating device located in the head plate;

Fig. 2 is a perspective view operating lever;

Figs. 3, 4 and 5 illustrate in a front, a side and a top view the manner of controlling the movement of the guide bar by means of a ring which is adjustable on the needle bar.

The needle bar oscillator 1 of the machine carries the threading device comprising primarily the guiding bar 2, the clamp member 3 which has secured to it at its lower end the threading hook which enters the eye of the needle during operation and the sliding member 4. Sliding mem her 4 supports a stud 5 and presents an angularly projecting lug 6 cut and bent out of the material of said member. The head plate 7 pivot-ally supports a two armed operating lever 8 secured thereto by means of a screw 9 constituting a pivot bolt.

A spring 10 is secured at one end in a circular groove 11 on a stud in the head plate 7 and at the other end to a bore 12 in the operating lever 8. A slot 13 is defined in one end of the operating lever to receive the lever is formed into a handle 14 projecting rearwardly from head plate 7.

Two ribs 16 projecting from the head plate 7 define a guiding groove for the lug 6. The springs 10 and 17 constitute parts of the spring system for operation of the threading device guiding bar 2 which is thus entirely encased in the head of the machine whereas in devices of the manipulating or of the prior art as: er "the springs was exposed on the bar 2 between the clamp member 3 and the lower bearing 18 of the threading device while another spring is located on the bar 2 in engagement with the sliding member 4.

These springs are now replaced in "a novel and more expedient manner by spring 17 whichi's anhcor'ed to lug 6 and to a pin 15 which projects through the guiding bar 2 and guide slot '19 of the slidirig member "4. The lower spring which was exposed and disposed around the bar is'now represented by spring '10.

Moving handle '14 oft he lever 8 upwardly 'while studs rests inslot 13 causes downward movement of the slide '4 and 'bar 2 while spring 1 is expanded until the hook arm carried -by clamp 3 is horizontally aligned with the eye oftlie needle of the machine. At that poiiit the downward movement ofthe bar 2 is stopped, for example, by the other end or the pm in slcjt1'9 striking a hat horizontal'abutment65 on a memberh iwhich is mounted on the needle bar *61 on which it is adjustable by means of set screws 62 and63. The pin "15, 'being guided in the slot 19 rotates 'the ba r and swings the pointed end of the 'hook arm into engagement with the needle eye. During the phase of the movement of the sliding member when the downward movement of the guiding bar 2 has ceased, the sliding member Continues tomove while the spring 17 is also e xpan'ded.

The movement of guided bar 2, 'relative'to the needle bar Will'be understood best if reference is had to Figs. 3, and S, explaining this subject matter as originally disclosed anddescribe d in Ser. No. 305,674, owned by the same assignee, g

The spring 17 holds the pin in the'lo wermo st position in the s1ot 19 during'dowii'ward movement of the sliding member fl. As soon as the'pin 15 engages the horizontal abutment "65 the downward moveme'rit' of the guiding bar -2 stops, while "the'sliding "rhernb'er 4 congnuezs to move, thus guiding pin 15 in slot 19 and rotating Releasingthe pressure on the handle 14 first'results in the spring 17 contracting and bar 2 movingback into normal angular position while being guided by the pin 15 inslot 19. Spring ltl'exerts pulling pressure on sliding memb'er lby way of stud 5 and moves the sliding member upwardly while bar 2 isrotated back to normal axial positionby pin 15 'whichisheldon abutment'6S by spring until thejend of pin "15'is engaged bythe lower end ofslot19. "Upon return of the bar 2"t'onormal axial position thekxi'ntinue'd pull of spring 10 'on the lever 8 returns the sliding member and the guide bar 2 to'the normal position illustrated in the drawing" by moving them vertically and upwardly.

Having now described the invention with reference to the embodiment shownfvvedo notwi'sh'to be limited thereto, but what \vedesireto protect by Letters Patent is set forth in the appended claims.

Operatingmeans for a needle" threading mechanism of the type including a guiding bar disposed parallel to the needle bar in the header a sewing machine and supporting a hook arm rotatable in a'horizontal plane for engagementwiththe eye of the needle, and a sliding member in engagement with said guiding member and having operative engagement with said op'erat'ing'means; said means includinga lever pivotally supported in the head of the machine having one erid presenting a handle extending outwardly through a slot in the'he'ad of the machine and one end provided'with an operating slot, 21 first spring extending between said lever and'a fixed point in the head ofthemaohiriefor maintaining said-lever in inoperative position, a guiding groove in thehead of the machine, a stud carried by said sliding member and eittending into said operating slotfor operation of said sliding member and the guiding bar in response to movement of said lever, a lugprojecting from said sliding member into said guiding groove to guide said sliding 4 member, and a second spring extending between anchoring points on said sliding member and said guiding *bar capable of biasing said sliding member to inoperative position on the guiding bar.

2. Operating means for a needle threading mechanism of the type including a guiding bar disposed parallel to the needle bar in the head of a sewing machine and supporting a hook arm rotatable in a horizontal plane for engagement with the eye of the needle, and a sliding member in engagement 'with said guiding member and having operative engagement with said "operating means; said means including a lever pivotally supported in the head of the machine having one 'end presenting a handle extending outwardly through a slot in the head of the machine and one end provided with anoperating-slot, a first spring extending between said lever and a fixed point in the head of the machine for maintaining said lever in inoperative position, a guiding groove in the head of the machine,a stud carried by'said sliding member'and extending into said operating slot for'operation'of said sliding member andthe g'uiding bar'in response tornovement of'said lever, a'lug projecting from said sliding memberinto said guiding groove to guidesaid'sliding member, and a second spring extending "between anchoring points on said 'slidingr'nerhber and's'a'id guiding 'barcapable'oi biasing said sliding memb'erto inoperative'position'on the guiding bar, said guidinggroove'extendinginsaid head plate substantially parallel tosaid'guiding bar.

I 3. Operating means for a needle'threading'mechanism of the typein'cluding a guiding bardisposed parallel to'the needle bar in the head of a sewing machine and supporting a hook arm rotatable in a horizontal plane for engagement with the 'eye of the needle, and a sliding member inengagement with said gtiiding'memb'er and having operative engagement with'said operatin'grneans; said means including a lever pivotally supportedinthe head of'the machine havingone end presenting a handle extending outwardly through'a slot in the header the machine and one end provided with arr-operating slot, a first spring extending'between said'lever and a fixed point in the headof the machine'for m'aintaining'said "lever in inoperative position, a guiding groove in the head ofthe machine, a stud carried by said sliding member and'extending into said operatingslot'for operation of said sliding member and theguiding'barin response'to movementof said lever, a lug projecting'from's'aid sliding member into saidguiding grooveto guide said'sliding membenand a second spring extendin'gbetween anchorin'g points on'said sliding member and said guidingb'ar capableof biasing said sliding member to inoperativeiposition'on theguiding bar, said'guiding'groove extending in said head plate substantiallyparallel'to said'guiding bar, and'said firstsprin'g being secured atone end'to said lever and atthe' other end to 'apivot on th'e'head-plate and being adapted to apply pressure to said stud on said sliding member byway of said operating slot.

4. Operating means for aneedle'threading'mechanism of the type'including a guiding bar disposed parallel to theneedle bar inthe head'of a sewing'machine and supporting a hook arm rotatable in ahorizontal plane for engagement 'with the eye of the'nee'dle, and asl'iding memberin engagement with'sa'id'guiding memberand having operative engagement with said operating means; said means including a leverpivotallysupportedinthe head of' the' machine'having'o'ne cnd presenting a handle extending outwardly through a 'slot inthe headof the machine and one end providedwithan operating slot,a first spring extending between said lever and a fixed point i'n'the head of the 'machine'forrnaintaining said'lever ininoperative'position, a guiding groove in the head of the machine,a stud carriedby said sliding member and extending into said operating slot for operation of said sliding member and the guiding barin response-to movement of said lever, a-lug projecting'from'saidsliding member into said-guiding groove tosguide-saidsliding member, and a second spring extending between anchorsaid second spring having one end secured to said lug ing points on said sliding member and said guiding bar and the other end to a member extending from said guidcapable of biasing said sliding member to inoperative ing bar through a slot in said sliding member. position on the guiding bar, said guiding groove extending in said head plate substantially parallel to said guid- 5 References Cited inthe file of this Pawnt ing bar, and said first spring being secured at one end UNITED STATES PATENTS to said lever and at the other end to a ivot on the head 640,919 Kobler Jan. 9, 1900 plate and being adapted to apply pressure to said stud on 2,544,577 Weber Man 6, 1951 said sliding member by way of said operating slot, and 

